Immune tolerance to self antigens prevents the onset of autoimmune diseases such as Multiple Sclerosis (MS). There are three branches of tolerance which allow the auto-aggressive potential of T lymphocytes to be limited; these are death, anergy-adaptation and regulation. The main body of this work attempts to clarify a role for adaptation in maintaining the sensitivity of the autoreactive T cell repertoire below a ‘threshold for harm’ in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). The well defined myelin basic protein (MBP) Ac1-9 epitope altered peptide ligand (APL) system has been used to develop a model allowing the examination of mechanisms underlying the adaptation of cells. Previous data showed immunisation with the 4Lys (wild-type) epitope mediated disease whereas a superagonist APL with a tyrosine substitution at position 4 (4Tyr) did not, despite showing potency in vitro. This was shown to be a result of both activation induced cell death and adaptation. Here an in vitro model was developed using MBP-reactive TCR transgenic cells to make predictions about the mechanisms underlying adaptation. These data lead to the conclusion that T cells can adapt (become less sensitive) either before or after encounter with the wild-type peptide, leading to a reversal of their pathogenic potential. The MBP APL system and MBP reactive transgenic cells were also used to assess the contribution of epitope spreading in a relapsing-remitting (RR) model of EAE induced with proteolipid protein. The cells were tracked and changes in phenotype and behaviour were monitored. The data show that disease induced with one antigen can be manipulated with cells relevant to a different antigen and that bystander suppression may be an effective weapon in controlling the progression to RR-EAE.

<p>Escherichia coli is a natural inhabitant of the intestines of both humans and animals, but there are also several pathogenic types of E. coli which cause disease in humans.</p><p>Strains of enterohemorrhagic E. coli (EHEC) have been associated with outbreaks of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome in humans. Most clinical signs of disease arise as a consequence of the production of shigatoxin 1 and 2 or combination of these toxins. Other major virulence factors include EHEC hemolysin and intimin, the product of the eae gene that is involved in attaching and effacing adherence phenotype. EHEC has also been associated with uncomplicated diarrhea.</p><p>The capacity to control EHEC disease and to limit the scale of outbreaks is dependent upon prompt diagnosis and identification of the source of infection.</p><p>The principal reservoirs of EHEC are cattle and food products, which presumably have come into contact with domestic animal manure and/or are inadequately pasteurised, these are important vehicles of infection.</p><p>In the present study, the PCR technique with primers detecting the verocytotoxin genes was shown to be a possible method to screen for and identify EHEC.</p><p>In summary stx genes were detected in 16 samples of 228 sampels and the eae gene was detected in 2 samples using PCR.</p>

Multiple sclerosis is a chronic autoimmune neurological disease characterized by inflammatory cell infiltration and demyelination in the central nervous system (CNS). It is considered to be mediated by Th1 and Th17 immune responses. Experimental autoimmune encephalomyelitis (EAE) is widely used as a mouse model to study MS as it has features and histopathology similar to that of MS. Tolerogenic dendritic cells (DC) are reported to efficiently prevent sensitization for EAE. In this research, we induced tolerogenic DC (DC10) by differentiating them with IL-10. Compared to immature DC, DC10 did not show increased expression of MHC II or the co-stimulatory molecules CD40, CD80 and CD86, and produced low levels of pro-inflammatory cytokines IL-1â, IL-6, and IL-12 but higher levels of IL-10. This is consistent with their possessing a tolerogenic phenotype. We found that three intraperitoneal (i.p.) injections of DC10 successfully inhibited the signs of established, ongoing EAE: DC10 significantly reduced the clinical scores, demyelination and cell infiltration in the spinal cord, as well as the production of IL-4, IL-6, IL-10, IL-17 and IFN-ã by spleen and lymph node (LN) lymphocytes. DC10 treatments did not significantly affect inflammatory cytokine mRNA levels in the CNS. We found that there was higher FoxP3 expression in the CNS in response to DC10 treatments relative to PBS-treated animals. We also found that DC10 treatments significantly enhanced IgG1, IgG2a and IgG2b production and total spleen and LN lymphocyte proliferation following challenge with myelin oligodendrocyte glycoprotein (MOG) antigen. As far as we know, this is the first report showing the successful therapeutic treatment with tolerogenic DC10 of established EAE in mice.

Escherichia coli is a natural inhabitant of the intestines of both humans and animals, but there are also several pathogenic types of E. coli which cause disease in humans. Strains of enterohemorrhagic E. coli (EHEC) have been associated with outbreaks of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome in humans. Most clinical signs of disease arise as a consequence of the production of shigatoxin 1 and 2 or combination of these toxins. Other major virulence factors include EHEC hemolysin and intimin, the product of the eae gene that is involved in attaching and effacing adherence phenotype. EHEC has also been associated with uncomplicated diarrhea. The capacity to control EHEC disease and to limit the scale of outbreaks is dependent upon prompt diagnosis and identification of the source of infection. The principal reservoirs of EHEC are cattle and food products, which presumably have come into contact with domestic animal manure and/or are inadequately pasteurised, these are important vehicles of infection. In the present study, the PCR technique with primers detecting the verocytotoxin genes was shown to be a possible method to screen for and identify EHEC. In summary stx genes were detected in 16 samples of 228 sampels and the eae gene was detected in 2 samples using PCR.

Multiple sclerosis is a chronic autoimmune neurological disease characterized by inflammatory cell infiltration and demyelination in the central nervous system (CNS). It is considered to be mediated by Th1 and Th17 immune responses. Experimental autoimmune encephalomyelitis (EAE) is widely used as a mouse model to study MS as it has features and histopathology similar to that of MS. Tolerogenic dendritic cells (DC) are reported to efficiently prevent sensitization for EAE. In this research, we induced tolerogenic DC (DC10) by differentiating them with IL-10. Compared to immature DC, DC10 did not show increased expression of MHC II or the co-stimulatory molecules CD40, CD80 and CD86, and produced low levels of pro-inflammatory cytokines IL-1â, IL-6, and IL-12 but higher levels of IL-10. This is consistent with their possessing a tolerogenic phenotype. We found that three intraperitoneal (i.p.) injections of DC10 successfully inhibited the signs of established, ongoing EAE: DC10 significantly reduced the clinical scores, demyelination and cell infiltration in the spinal cord, as well as the production of IL-4, IL-6, IL-10, IL-17 and IFN-ã by spleen and lymph node (LN) lymphocytes. DC10 treatments did not significantly affect inflammatory cytokine mRNA levels in the CNS. We found that there was higher FoxP3 expression in the CNS in response to DC10 treatments relative to PBS-treated animals. We also found that DC10 treatments significantly enhanced IgG1, IgG2a and IgG2b production and total spleen and LN lymphocyte proliferation following challenge with myelin oligodendrocyte glycoprotein (MOG) antigen. As far as we know, this is the first report showing the successful therapeutic treatment with tolerogenic DC10 of established EAE in mice.

No description available.

Background: Multiple sclerosis (MS) is a chronic, neurological disease characterized by targeted destruction on central nervous system (CNS) myelin. The autoimmune theory is the most widely accepted explanation of disease pathology. Circulating Th-1 cells become activated by exposure to CNS-specific antigens such as myelin basic protein. The activated Th-1 cells secrete inflammatory cytokines, which are pivotal for inflammatory responses. We hypothesize that enhanced production of inflammatory cytokines triggers cellular events within the dorsal root ganglia (DRG) and/or spinal cord, facilitating the development of neuropathic pain (NPP) in MS. NPP, the second worst disease-induced symptom suffered by patients with MS, is normally regulated by DRG and/or spinal cord. Objective: To determine gene and protein expression levels of tumor necrosis factor-alpha (TNF ) within DRG and/or spinal cord in an animal model of MS. Methods: Experimental autoimmune encephalomyelitis (EAE) was induced in adolescent female Lewis rats. Animals were sacrificed every 3 days post-disease induction. DRG and spinal cords were harvested for protein and gene expression analysis. Results: We show significant increases in TNF expression in the DRG and of EAE animals at peak disease stage, as assessed by clinical symptoms. Conclusion: Antigen-induced production of inflammatory cytokines such as TNF within the DRG identifies a potential noel mechanism for MS-induced NPP.

No description available.

Background: Multiple sclerosis (MS) is a chronic, neurological disease characterized by targeted destruction on central nervous system (CNS) myelin. The autoimmune theory is the most widely accepted explanation of disease pathology. Circulating Th-1 cells become activated by exposure to CNS-specific antigens such as myelin basic protein. The activated Th-1 cells secrete inflammatory cytokines, which are pivotal for inflammatory responses. We hypothesize that enhanced production of inflammatory cytokines triggers cellular events within the dorsal root ganglia (DRG) and/or spinal cord, facilitating the development of neuropathic pain (NPP) in MS. NPP, the second worst disease-induced symptom suffered by patients with MS, is normally regulated by DRG and/or spinal cord. Objective: To determine gene and protein expression levels of tumor necrosis factor-alpha (TNF ) within DRG and/or spinal cord in an animal model of MS. Methods: Experimental autoimmune encephalomyelitis (EAE) was induced in adolescent female Lewis rats. Animals were sacrificed every 3 days post-disease induction. DRG and spinal cords were harvested for protein and gene expression analysis. Results: We show significant increases in TNF expression in the DRG and of EAE animals at peak disease stage, as assessed by clinical symptoms. Conclusion: Antigen-induced production of inflammatory cytokines such as TNF within the DRG identifies a potential noel mechanism for MS-induced NPP.

In den letzten Jahren ist zunehmend deutlich geworden, dass die Multiple Sklerose (MS) nicht nur eine Erkrankung der weißen Substanz des zentralen Nervensystems ist, sondern auch häufig und beträchtlich die graue Substanz in allen klinischen Verlaufsformen betrifft. Besonders die kortikale Pathologie mit entmarkten Läsionen wurde durch verbesserte immunhistochemische Färbetechniken und neuen magnetresonanztomographischen Verfahren ausführlicher untersucht. MS-Patienten leiden klinisch oft an körperlichen Beeinträchtigungen und neuropsychologischen Defiziten, welche die Lebensqualität beeinflussen. Diese Symptome wurden mit Läsionen in der grauen Substanz assoziiert. Mechanismen, die zu dieser Pathologie führen, müssen daher aufgeklärt werden um vorbeugende oder akute Behandlungen entwickeln zu können. Zur pathologischen Untersuchung der grauen Substanz werden angemessene Tiermodelle benötigt, welche die humane kortikale Pathologie wiederspiegeln. Das am häufigsten verwendete Tiermodell in MS-Studien ist die Experimentelle Autoimmune Enzephalomyelitis (EAE), die in ihrem ‘konventionellen’ Immunisierungsprotokoll nur selten den zerebralen Kortex betrifft. Ein EAE-Modell mit Einbezug des Kortex, das MS-Läsionen nachahmt, wurde in Ratten beschrieben. Hierzu wurden proinflammatorische Zytokine in eine vorbestimmte kortikale Region injiziert. Da spezifisch genveränderte Rattenstämme fehlen um die Mechanismen der Pathologie in der grauen Substanz zu untersuchen ist es notwendig das Tiermodell in Mäusen zu entwickelen. Das Ziel dieses Projekts war die Entwicklung eines kortikalen EAE-Mausmodells sowie dessen histopathologische Charakterisierung. Desweiteren wurde kortikales Gehirnmaterial von MS-Patienten im späten Krankheitsstadium auf dendritische Patholgie untersucht. Die kortikale EAE wurde in Myelin Oligodendrozyten Glykoprotein (MOG)-immunisierten BiozziABH (hohe Antikörper) und F1 Nachkommen, die aus BiozziABH und Mäusen mit einem C57BL6/J-Hintergrund generiert worden sind, durch die intrakortikale Injektion von TNF-α und IFN-γ induziert. Histologische Untersuchungen zeigten eine ausgedehnte subpiale Entmarkung und Entzündung im Kortex drei Tage nach der Zytokininjektion in der betroffenen Hirnhälfte. Die Entzündung ging innerhalb von drei Wochen fast vollständig zurück und entmarkte Regionen wiesen teilweise eine Remyelinisierung auf. Axone blieben in läsionalen Regionen erhalten und neuronaler Verlust wurde im Kortex nicht beobachtet. Desweiteren wurde eine Methode etabliert, die es erlaubt detailliert dendritische Pathologien in der Maus zu untersuchen. Kortex-enthaltenes Autopsiematerial von progressiven MS-Patienten mit langandauerndem Krankheitsverlauf zeigte einen Verlust von dendritischen Dornfortsätzen (Spines) in Neurone, die in den unteren korikalen Layern sowohl in chronisch entmarkten Läsionen als auch im umliegenden normal erscheinendem Gewebe der grauen Substanz lokalisiert waren. Im vorliegenden Projekt wurde ein kortikales EAE-Mausmodell entwickelt, das die humane MS-Pathologie der grauen Substanz in frühen Krankheitsstadien wiederspiegelt. Dieses Modell ist für Untersuchungen früher Mechanismen im entmarkten Kortex und für die Erprobung therapeutischer Behandlungen wie die Erhöhung der Remyelinisierung nützlich. Darüberhinaus wurde ein ausgedehnter Verlust dendritischer Dornfortsätze im zerebralen Kortex in chronischen MS-Patienten gezeigt, der auf oft beobachtete neuropsychologische Defizite zurückgeführt werden könnte.